I feel like we just had this discussion.
The users on my site do trading a lot and you have good trader and bad traders. So, we have a Good & Bad Traders forum and ask that users start a thread using the format of "Good Trader: Username" or "Bad Trader: Username". If someone starts one of those threads about someone, we ask that they give some details or why they rate them Good or Bad. It works pretty well and is easily searchable.